What invention made it possible to calculate latitude? why couldn’t columbus calculate longitude?

Question 1:

Latitude was often measured by using the quadrant and the astrolabe.

Question 2:

Measuring longitude at sea was extremely difficult in the past. The lack of a stable surface to work from and the inability to repeat determinations over time made it impossible to use the methods that were used on land. Many European countries promised prizes and riches to those who could figure out a way to do it, in one of the largest scientific enterprises in history.

african american women made meaningful gains in the labor force and us armed forces as a result of the wartime labor shortage during the second world war, but these advances were sharply circumscribed by racial segregation, which was legal in all parts of the country, and virulent racism in the dominant culture. president franklin roosevelt’s signing of executive order 8802 in 1941 banned race discrimination in defense industries and civil service jobs. it was rarely enforced, however, and mostly ignored by employers until they were forced to hire nonwhites by exhaustion of the white labor supply. even then, war industries often filled their most menial and dangerous positions with black employees, frequently on night shifts and in janitorial slots. african american women suffered both racial and gender discrimination, so they had to fight very hard even to enter skilled spots on the production line in aircraft, shipyard work, and other well-paying war industries.

entrenched racist attitudes on the part of white employers and coworkers in the nation’s war-production centers hindered black women’s ability to gain employment in these unionized blue-collar jobs. when black people did get hired, they often were forced to use separate restrooms and to perform the lowest paid, most difficult work. sometimes their employment triggered hate strikes, which erupted periodically over the war, when white workers walked off the job over promotion or hiring of african americans into previously restricted departments and occupation categories. in 1943, for example, a baltimore western electric plant was forced to build separate toilet facilities for white and black workers when white women demanded them. barred from most service occupations like telephone operator, clerical worker (other than federal offices in washington, dc), or waitress at white restaurants, black women mainly found war jobs in dangerous industries such as munitions plants.

african american women

the difficulty for black women entering skilled production areas, retail and other service work, or transportation jobs during the 1940s is mirrored in their continuing dominance of the private market for maids. although during the war, the proportion of african american women who were working in domestic service fell dramatically, from 60 to 44 percent, domestic employment remained their primary occupation category throughout the war. even in the military, which they did enter as a support for black male soldiers in the segregated armed forces, black women had trouble escaping low-skilled assignments, and they were not allowed to take combat roles. six african american wacs, for example, were court-martialed at fort devens, massachusetts, when they refused to take custodial assignments. in her memoir of being the first african american to join the women’s army corps, charity adams earley mentions the common army practice of dividing into "white" and "colored" the jobs wacs were given, with the latter being menial and

japans americans

japanese americans in military during world war ii in world war ii for its size and length of service, japanese americans served in the u.s. armed to nisei veterans in general—"most of the others did extremely well in their work and lives.

explanation:

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